Prosecutors are typically lawyers who possess a law degree, and are recognized as legal professionals by the court in which they intend to represent society (that is, they have been admitted to the bar).

They usually only become involved in a criminal case once a suspect has been identified and charges need to be filed. They are typically employed by an office of the government, with safeguards in place to ensure such an office can successfully pursue the prosecution of government officials. Often, multiple offices exist in a single country, especially those countries with federal governments where sovereignty has been bifurcated or devolved in some way.

Since prosecutors are backed by the power of the state, they are usually subject to special professional responsibility rules in addition to those binding all lawyers. For example, in the United States, Rule 3.8 of the ABA Model Rules of Professional Conduct requires prosecutors to "make timely disclosure to the defense of all evidence or information ... that tends to negate the guilt of the accused or mitigates the offense." Not all U.S. states adopt the model rules, however U.S. Supreme Court cases and other appellate cases have ruled that such disclosure is required. Typical sources of ethical requirements imposed on prosecutors come from appellate court opinions, state or federal court rules, and state or federal statutes (codified laws).

In Australia, at least in the case of very serious matters, the DPP will be asked by the police, during the course of the investigation, to advise them on sufficiency of evidence, and may well be asked, if he or she thinks it proper, to prepare an application to the relevant court for search, listening device or telecommunications interception warrants.

More recent constitutions, such as South Africa's, tend to guarantee the independence and impartiality of the DPP.

Though Scots law is a mixed system, its civil law jurisdiction indicates its civil law heritage. Here, all prosecutions are carried out by Procurators Fiscal and Advocates Depute on behalf of the Lord Advocate, and, in theory, they can direct investigations by the police. In very serious cases, a Procurator Fiscal, Advocate Depute or even the Lord Advocate, may take charge of a police investigation. It is at the discretion of the Procurator Fiscal, Advocate Depute or Lord Advocate to take a prosecution to court, and to decide on whether or not to prosecute it under solemn procedure or summary procedure. Other remedies are open to a prosecutor in Scotland, including fiscal fines and non-court based interventions, such as rehabilitation and social work. All prosecutions are handled within the Crown Office and Procurator Fiscal Service. Procurators fiscal will usually refer cases involving minors to Children's Hearings, which are not courts of law, but a panel of lay members empowered to act in the interests of the child.

Prosecutors are typically civil servants who possess a university degree in law, and additional training in the administration of justice. In some countries, such as France and Italy, they belong to the same corps of civil servants as the judges.

In Belgium, the Senior Crown prosecutor, or Procureur du Roi / Procureur des Konings (or Procureur Général / Procureur-Generaal in appellate courts and in the Supreme Court), is supported by crown prosecutors (substituts / substituten). He opens preliminary investigations and can hold a suspect in custody for 24 hours. When necessary, a Crown prosecutor will request an examining judge (juge d'instruction/onderzoeksrechter) be appointed to lead a judicial inquest. With a judge investigating, Crown prosecutors do not conduct the interrogatories, but simply lays out the scope of the crimes which the judge and law enforcement forces investigate (la saisine). Like defense counsel, Crown prosecutors can request or suggest further investigation be carried out. The Crown prosecutor is in charge of policy decisions and may prioritize cases and procedures as need be. During a criminal trial, prosecutors must introduce and explain the case to the trier, i.e., judges or jury. They generally suggest a reasonable sentence which the court is not obligated to follow; the court may decide on a tougher or softer sentence. Crown prosecutors also have a number of administrative duties. They may advise the court during civil actions. Under Belgian law, judges and prosecutors are judicial officers with equal rank and pay. The Minister of Justice can order but not forbid a criminal investigation (droit d'injonction positive / positief injunctierecht).

In Brazil, the public prosecutors form a body of autonomous magistrates - the Ministério Público (literally Public Ministry) - working both at the federal and state level. The procuradores da República - federal prosecutors - are divided in three ranks, according to the jurisdiction of the courts before which they officiate, thus the "procuradores da República" (federal prosecutors) officiate before single judges and lower courts, "procuradores regionais da República" (prosecutors who officiate before federal appellate courts), and "subprocuradores gerais da República" (prosecutors who officiate before the superior federal courts). The Procurador Geral da República heads the federal body, and tries cases before the Supremo Tribunal Federal (STF), Brazil's highest court, in charge of judicial review and the judgment of criminal offenses perpetrated by federal legislators, members of the cabinet, and the President of Brazil. At the state level, the career is usually divided in "promotores de Justiça" (state prosecutors), which officiate before the lower courts, and "procuradores de Justiça" (prosecutors officiating before the states' court of appeals). There are also military prosecutors whose career, although linked to the federal prosecutors, is divided in a manner similar to state prosecutors.

In Brazil the prosecutors' main job is to promote justice, as such they have the duty of not only trying criminal cases, but, if during the trial, they become convinced of a defendant's innocence, requesting the judge to acquit him. The prosecutor's office has always the last word on whether criminal offenses will or will not be charged, with the exception of those rare cases in which Brazilian law allows for private prosecution. In such cases, the prosecutor will officiate as custos legis, being responsible to ensure that justice is indeed carried out. Although empowered by law to do so, prosecutors conduct criminal investigations only in major cases, usually involving police or public officials' wrongdoings. Also, they are in charge of supervising police work and directing the police in their investigations. The power of individual prosecutors to hold criminal investigations is still controversial and, although massively supported by judges, prosecutors and the general population, it is being contested before the Supremo Tribunal Federal. Beside their criminal duties, Brazilian prosecutors are among those authorized by the Brazilian constitution to bring action against private individuals, commercial enterprises, and the federal, state and municipal governments, in the defense of minorities, the environment, consumers, and the civil society in general.

In France, the Office of the Prosecutor includes a Chief Prosecutor, or Procureur de la République (or procureur général in an appellate court or in the Supreme Court) assisted by deputy prosecutors (avocats généraux) and assistant prosecutors (substituts). The Chief Prosecutor generally initiates preliminary investigations and, if necessary, asks an examining judge, or juge d'instruction, be assigned to lead a formal judicial investigation. When an investigation is led by a judge, the prosecutor plays a supervisory role, defining the scope of the crimes being examined by the judge and law enforcement forces. Like defense counsel, the chief prosecutor may petition or motion for further investigation. During criminal proceedings, prosecutors are responsible for presenting the case at trial to either the Bench or jury. They generally suggest advisory sentencing guidelines, but it remains at the Court's discretion to decide its own sentence, increased or reduced as it sees fit. In addition, prosecutors have several administrative duties.

Prosecutors are considered by French law as magistrates (as in most civil law countries). While the defense and plaintiff are both represented by common lawyers, sitting on the ground in the courtroom, the prosecutor sits on a platform as the court does, although he doesn't participate in deliberation. Judges and prosecutors are trained in the same school, and regard each other as colleagues.

In Germany, the Staatsanwalt (literally 'state attorney') is a life-tenured public official in the senior judicial service. The Staatsanwalt heads pre-trial criminal investigations, decides whether to press a charge or drop it, and represents the government in criminal courts. He not only has the "professional responsibility" not to withhold exculpatory information, but is also required by law to actively determine such circumstances and to make them available to the defendant or his/hers defense attorney. In case he is not convinced of the defendants guilt, the state attorney is required to plead against or in favour of the defendant according to the prosecutor's own assessment (RiStBV, No. 138/139). Prosecution is compulsory if the prosecutor has sufficient evidence to convict.[6]

In Italy, a Prosecutor's Office is composed of a Chief Prosecutor (procuratore capo) assisted by deputy prosecutors (procuratori aggiunti) and assistant prosecutors (sostituti procuratori). Prosecutors in Italy are judicial officers just like judges and are ceremonially referred to as Pubblico Ministero/ Public Ministry' (or P.M.)

Italian Prosecutors officiate as custos legis, being responsible to ensure that justice is indeed carried out. They are obligated under the Constitution to initiate preliminary investigations once they are informed or take personal notice of a criminal act, the so-called notitia criminis, or receive a bill of complaint. They can make direct investigations or conduct them through orders and directives given to (judicial) police detectives (which anyway have the chance to make their own parallel investigations in coordination with the Prosecutor): if enough evidence has been gathered in order to proceed, the prosecution is compulsory and it must move from preliminary investigations to initiate trial proceedings.[7] At trial, the prosecuting attorney has to handle the prosecution but is prohibited from withholding exculpatory evidence, for they have to promote justice, which means that they have the duty of not only trying criminal cases, but, to request the judge to acquit him if, during the trial, they become convinced of a defendant's innocence, or agree that there is no evidence, beyond any reasonable doubt, of his guiltiness.

In appellate courts, the Office of the Prosecutor is called Procura Generale and the Chief Prosecutor Procuratore Generale (PG). The Procuratore Generale presso la Corte di Cassazione is the Chief General Prosecutor before the Corte di Cassazione, the Supreme Court of Italy.

Prosecutors are allowed during their career to act in the other's stead, but a recent ruling by the Italian Constitutional Court stated that prosecutors, who wish to become judges, must relocate to another region and are prohibited to sit or hear trials that they themselves initiated.

In Japan, public prosecutors kensatsu-kan(検察官?) are professional officials who have considerable powers of investigation, prosecution, superintendence of criminal execution and so on. Prosecutors can direct police for investigation purposes, and sometimes investigate directly. Only prosecutors can prosecute criminals in principle, and prosecutors can decide whether to prosecute or not. High-ranking officials of the Ministry of Justice are largely prosecutors.

Prosecutors are the public officials who are members of the ministry of Justice.

Prosecutors can conduct crime investigations directly or indirectly. They are responsible for the entire process of investigations and court prosecutions. Since Korean modern law was designed after continental system, the role of Korean prosecutors is similar or identical to that of European equivalents in commanding investigations, determining indictable cases and prosecuting process. Korean prosecutors take pride in successful prosecutions of former presidents(1995) and sons of the incumbent presidents(1997 and 2002). Besides, they have made important contributions to convicting many corrupt high-ranking officials and business leaders.[8]

In Sweden, public prosecutors are lawyers who work out of the Swedish Office of Public Prosecutions (Åklagarmyndigheten) and direct police investigations of serious crimes. For all criminal cases, public prosecutors decide arrests and charges on behalf of the public and are the only public officers who can make such decisions. Plaintiffs also have the option of hiring their own special prosecutor (enskilt åtal). The exception is cases concerning crimes against the freedom of the press for which the Attorney General acts as the prosecuting attorney. In court, the prosecutor is not necessarily in an adversarial relationship to the defendant, but is under an obligation to investigate and present information which may incriminate or exhonerate the defendant. He is not a judicial officer, nor does he participate in the private deliberations of the court.

Public prosecutors are the only public officers who can decide to appeal cases to appellate courts (hovrätter). Otherwise, appeals are initiated by defense counsel, the plaintiff, their representatives, and other parties to the case (målsäganden). When a case has been decided by an appellate court, the right to appeal to the Supreme Court passes from the case's prosecutor to the Director of Public Prosecutions (Riksåklagaren).

A Public Procurator is an office used in Socialist judicial systems which, in some ways, corresponds to that of a public prosecutor in other legal systems, but with more far-reaching responsibilities, such as handling investigations otherwise performed by branches of the police. Conversely, the policing systems in socialist countries, such as the Militsiya of the Soviet Union, were not aimed at fulfilling the same roles as police forces in Western democracies.

A Public Procurator is a position in the People's Republic of China, analogous to both detective and public prosecutor. Legally, they are bound by Public Procurators' Law of the People's Republic of China. According to Article 6, the functions and duties of public procurators are as follows:

Supervise the enforcement of laws according to law.

Public prosecution on behalf of the State.

Investigate criminal cases directly accepted by the People's Procuratorates as provided by law.

In many countries, the prosecutor's administration is directly subordinate to the executive branch (e.g. the US Attorney General is a member of the President's cabinet). In some other countries - such as Italy or Brazil - the prosecutors are judicial civil servants and so their hierarchy is installed with the same (or nearly the same) liberties and independence warranties which the judges traditionally enjoy.

In other countries, a form of private prosecution is available, meaning person(s) or a private entity can directly petition the courts to hold trial against someone they feel is guilty of a crime, should the prosecutor refuse to indict him/her.

In the early history of England, the victim of a crime and his family had the right to hire a private attorney to prosecute criminal charges against the person alleged to have injured the victim.[9] In the 18th century, prosecution of almost all criminal offences in England was private, usually by the victim.[10] In colonial America, because of Dutch (and possibly French) practice and the expansion of the office of attorney general, public officials came to dominate the prosecution of crimes. However, privately funded prosecutors constituted a significant element of the state criminal justice system throughout the nineteenth century.[11] The use of a private prosecutor was incorporated into the common law of Virginia and is still permitted there.[9]Private prosecutors were also used in North Carolina as late as 1975.[12] Private prosecution has been used in Nigeria, but the practice is being phased out.[13]

Bruce L. Benson's To Serve and Protect lauds the role of private prosecutors, often employed by prosecution associations, in serving the needs of crime victims in England. Radical libertarian theory holds that public prosecutors should not exist, but that crimes should instead be treated as civil torts. Murray Rothbard writes, "In a libertarian world, there would be no crimes against an ill-defined 'society,' and therefore no such person as a 'district attorney' who decides on a charge and then presses those charges against an alleged criminal."[14] Private prosecution has been cited as a remedy for district attorneys' unwarranted inaction.[15]